Based on dynamic data of land utilization in Yan'an City from 1989 to 2012,this paper studies temporal and spatial variation characteristics,dynamic degree and intensity of land utilization.Moreover,this paper uses landscape dominance,landscape evenness and other landscape pattern indices to analyze the landscape pattern changes of Yan'an City.The results are as follows:from 1989 to 1999,the utilization area changes of main lands in Yan'an City were small.From 1999 to 2012 after farmland returning to woodland,the changes of land utilization area sped up;the biggest decline of land was plowland,while the biggest increase was woodland;the change intensities of plowland and woodland were much larger than other types of land.The difference of indices of land utilization change before and after farmland returning to woodland was relatively big;the index after farmland returning to woodland was significantly greater than the counterpart before farmland returning to woodland.The main bodies of land utilization change after farmland returning to woodland are plowland and woodland;the implementation of project promotes the turnover of plowland to woodland.The landscape pattern changes of Yan'an City took the implementation of grain-to-green program(GTGP)as the node.The dominance of land utilization drops after going,while evenness goes up after dropping.The implementation of the project increases the dominance degree of ecological lands which is based on woodland on land utilization.However,as woodlands increase and plowlands and grassland decrease,the homogeneity and richness of land utilization reduce.The land utilization in the future should attach great importance to the consolidation and protection of ecological environment construction achievements.%以延安市1989-2012年土地利用动态数据为基础,研究了土地利用的结构、动态度、强度等时空变化特征,并采用景观优势度和景观均匀度等景观格局指标对景观格局变化进行分析.结果表明,退耕前的1989-1999年,延安市各主要土地利用面积变化均不大;退耕后的1999-2012年,土地利用面积变化加快,面积减少最多的为耕地,增加最多的为林地,耕地和林地变化强度远大于其他类型土地;退耕前后的土地利用变化强度指数差异较大,退耕后明显大于退耕前;退耕还林工程的实施有效推动了耕地向林地的流转.延安市景观格局变化以退耕还林工程实施为节点,土地利用优势度先降后升,均匀度先升后降,工程的实施提高了以林地为主体的生态用地对土地利用的支配程度;但随着林地增加,耕地和牧草地减少,土地利用均匀性降低,土地利用丰富度减小,在以后的土地利用中要注重对生态环境建设成果的巩固和保护.
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